Method of safeguarding stills.



W. M. BURTON. METHOD OF SAFEGUARDING STILLS.

APPLICATION FILED JAN. 23. I915.'

11.,16 689 Patented Nov. 16, 1915.

tUFiQ ii WILLIAM M. BURTON, OF CHICAGO, ILLINOIS, ASSIGNOR TO STANDARD OIL COMPANY, OF WHITING, INDIANA, A CORPORATION OF INDIANA} METHOD OF SAFEG'UARDING STILLS.

Specification of Letters Patent.

1 Patented Nov. 16, 1915.

Application filed January 23, 1915. Serial No. aces.

To all whom it may concern: Be it known that I, WILLIAM M. BURTON. a citizen of the United States, residing at 72 West Adams street, Chicago, in the county of Cook and State of Illinois, have invented a new and useful Method of Safeguarding Stills, of which t e following is a specification. I

My invention relates to improvements in the art of distillation, and more particularly to a method of safeguarding pressure stills in which combustible fluid is contained.

My invention is more immediately directed to a method of safeguarding or protecting petroleum stills, such, for instance, as are employed in the manner set forth in my Patent No. 1,049,667, January 7, 1913.

According to the method of distilling petroleum set forth in the patent above referred to, certain petroleum products are distilled under a pressure indicative of a distillation temperature higher than the ignition point of the gases produced within the still. Under such circumstances the problem of effectively safeguarding the still becomes a peculiarly difi'icult one, and it is with this specific problem in mind that I have designed the improvements set forth in the following specification.

In operating a pressure still in the manner set forth in my patent above referred to,

I find that if the common form of safety valve construction be used for relieving expressure within the still, the opening of the safety valve and the venting of the escaping gases to the atmosphere brings about a most disastrous result, 21 6., due to the excessively hightemperature and pressure of distillation made use of, the escaping gases, or some of them, immediately take fire upon coming into contact with the atmosphere. The safety valve and the adjacent portions of the still are immediately enveloped in a flame of exceedingly high temperature, and there is great danger of injury, not only to these parts, but to the surrounding stills, condensers, and other structures. It will be appreciated that in a plant in which the distillation of such com; bustible products, as petroleum, is carried out upon a large scale, the frequent recurrence of this highly dangerous condition imposes an intolerable hazard upon the operation of the plant.

To remedy these difficulties previously .nace is thereby lessened, and

met with in safeguarding such pressure stills, I employ a method which consists essentlall in venting the escaping gases into a cham er of sufiicient capacity to permit of their expansion and cooling to a temperature well below the ignition point of the most inflammable gaseous constltuent. After having been expanded and cooled within this chamber and out of contact with the atmosphere, the gases may then pass to the atmosphere without danger of spontaneous ignition. In carrying out themethod of safeguarding the still thus briefly outlined, I further find it desirable to vent the gases to the atmosphere at a point comparatively remote from the still. The danger of the gases becoming ignited from the still furin the event that the outgoing gases should, by accident, become ignited, it is possible to promptly stop the confiagration by manually shutting off the safety valve for an instant, as the same is so far removed from the point at which the gases are burning as to be easily reached by an operator.

In carrying out my invention I prefer to make use of the form of apparatus shown in the accompanying drawings, in Which- Figure l is a broken sectional View of a still equipped with my improved valve which is shown broken .and in elevation, and Fig. 2 is an enlarged sectional view of the valve and the safety pipe connected thereto, the latter being broken out in its central portion.

The still 3, shown in part in Fig. 1, is, like that in the aforesaid patent, used for distilling liquid hydrocarbon of high-boiling-point, such as fuel oil, by heat applied to the still. A safety valve 4 is connected With the still by a trap 5, shown to consist of a curved section 6 leading to the bottom of the valve, and an extension 7 connected with the top of the still. The trap-section 6 contains, in the use of the device, a liquid, preferably hydrocarbon, like that undergoing distillation, and the supply thereof in the trap which should extend to the level indicated by the dotted line 19, may beintroduced through the T-joint 10 connecting the sections 6 and 7 on withdrawing a block 11 normally blanking the top end of the T. The safety valve shown comprises a casing having a discharge opening 12, a hood 13 secured on the casing to extend from an opening 14 in its top and containing a screwplug'15 through which passes the stem 16 of a conical valve 17, and a spiral spring 18 confined between the valve and plug to enable-its tension to be regulated by threading the plugin and out of the tapped bore of the hood 13. The valve is thus held against its seat in the casing at the mouth of the trap-section 6 by the adjusted tens on of the spring 18 to resist any predetermined pressure exerted from the still. If the valve is so seated as to be exposed to'vapors arising from the contents of the still, it would stick at its seat by the deposit on it of carbon or by corrosion, or both, and it might thusfail to respond to the pressure for wh1ch it is set. This is avoided by inter-posing the trap 5 between the valve and still, since the liquid contained in the section 6 forms an effective seal against the vapors reaching the valve, which thus remains clean; and n the event of excessive pressure occurring in the still, it acts to force the liquid, like a plunger, against the valve to unseat the latter and permit of the escape of the vapors.

Connected to the outlet openlng 12 of my safety valve, as by a threaded flange 19 and elbow 20, is a comparatively long relief-pipe 21 which extends vertically upward. In practice, I have found that a safety valve having an outlet opening three inches in diameter should be provided with a vent or relief-pipe about fifteen feet in height into which the vapors expand and through which they must pass before'reaching the atmosphere.

My pipe is in relation to its diameter, and pressure of the gases, that the walls of the pipe which are normally at approximately atmospheric temperature will so expand and cool the escaping gases as to bring them safely below their ignition temperature before they are permitted to reach the atmosphere. As before stated, this result is effectively accomplished in the particular construction of the valve presented by Way of illustration, by a pipe about three inches in diameter and fifteen feet in length where the still temperature and pressure are in the neighborhood of 800 F. and 4 atmospheres, respectively. I

It will further be apparent that if, by any mischance, the vapors should become ignited as they issue from the vent pipe, the flame will be so far removed from the distilling apparatus and from the safety valve that there will be no immediate danger to either, and an attendant may readily reach the valve for turning off the same if that is considered necessary or desirable.

By my improved construction of safetv designed to be of such length valve the hazards of operating a still of combustible material under the high temperatures and pressures employed have been greatly reduced.

While I have described in considerable detail one manner of carrying out my invention and a form of apparatus suitable for use according to this method, and have set forth the peculiar advantages of the invention as applied to the art of distilling petroleum oils, it is to be understood that I do not regard the invention as limited to the specific details set forth, nor to its applicability to this art alone, but on the contrary, I wish my invention to be limited in scope only by the terms of the following claims in which it is my intention to claim all novelty inherent in the invention as broadly as the prior art will permit.

What I claim as new and desire to secure by Letters Patent is 1. The method of safeguarding pressure stills containing combustible gases and in which the stilltemperature approximates the ignition temperature of the gases, which consists in automatically opening an outlet from such stllls when the internal pressure becomes excessive, expanding and cooling the outgoing gases below their ignition point but not below their condensation point while out of contact with the atmosphere, and venting such previously cooled gases to the atmosphere.

2. The method 'of safeguarding pressure stills containing combustible fluid and in which the still temperature approximates the ignition temperature of the fluid, which con- 'sists in automatically opening an outlet from such stills when the internal pressure becomes excessive, cooling the outgoing fluid below its ignition temperature while out of contact with the atmosphere, and venting such previously cooled fluid to the atmosphere at a point remote from the still.

3. The method of safeguarding pressure stills containing combustible gases and in i WILLIAM M. BURTON.

In presence o f J. D, R001, R. M. POWELL. 

